CDKN2A and hereditary chronic pancreatitis: This study also calculated the NNS for specific HRI groups, with a NNS of 250 for a PV in BRCA genes, 130 for PRSS1/SPINK1 (hereditary pancreatitis), 71 for STK11/LKB (PJS) and 51 for a PV in the CDKN2A gene.